Cylindrical cork closures are commonly used in wine bottles. Cut from natural cork, the closure is an elastic liquid-proof material that has a diameter that is slightly larger than the inner diameter of the neck of the bottle so that when it is compressed and inserted into the neck of the bottle it seals the bottle and forms a leak-proof closure. The closure is usually placed so that its outer face is essentially flush with the opening lip of the bottle. The closure may include a wrapper or capsule that covers the outer face of the closure and surrounds the neck to protect against contamination. With the advent of the cork, however, and especially where the cork was installed flush with the lip of the bottle, the need for extraction became the necessity for which the corkscrew was invented.
The traditional corkscrew in its simplest form is a metal helix or solid screw with an attached handle for manipulation. The corkscrew requires some skill in use with the objective being to withdraw the cork from the bottle whole and intact. An unsuccessful withdrawal can result in a broken cork that has to be dug out or pushed into the bottle. Either result is undesirable and is displeasing to the user. Other configurations of cork extractors have been developed over the years as described by Bernard Watney and Horner Babbidge in Corkscrews for Collectors (Philip Wilson Publications, London, England, 1981), but the helix or solid corkscrews still are the predominant tools.
Watney and Babbidge also describe the correct procedure and objectives for achieving a successful withdrawal. It requires (a) centering the axis of the corkscrew on the face of the exposed closure and (b) with a twisting motion advance it along the axis of the closure until sufficient material is engaged to permit withdrawing the closure without cracking or breaking the cork material. Deviation from these actions can result in the corkscrew advancing to the side of the closure where it becomes cramped against the neck of the bottle and may require additional force to withdraw or even bending of the corkscrew. At the very least this impairs the extraction by limiting further penetration and produces anxiety. Worse it may cause tearing or fracture of the cork requiring additional work to open the bottle and destroying the pleasure of the moment. And at worst, the glass of the bottle may be broken, making the wine unusable.
In the hands of a skilled user, these failures seldom occur, but even so do occur as described in the article “Corkscrews that Work” by Paul Fredericksen (Wine Review, May 1946). In the hands of a novice or occasional user, the rate will certainly rise, if not to a large number in absolute terms, then at least sufficient to cause some reluctance by the consumer in choosing a corked bottle. As evidence that the simple task of extracting a cork does challenge the user, observe the historical variety as described in Corkscrews for Collectors, and “Symptoms of Withdrawal” (H. Kraus and H. Babbidge, The Chartered Mechanical Engineer, Britain, December 1977) and U.S. patents as well as the current selection of devices on the market that address the problem of central positioning and guidance. Most achieve this result by providing a rigid housing that rides on the exposed lip of the bottle while holding the helix of the corkscrew in a central location with respect to the closure (Paul Fredericksen, Wine Review, May 1946). Yet the simple direct-pull and lever-pull corkscrews that rely upon the user's skill to centrally locate and axially guide the screw are still sold in abundance.
For fine wines that improve with age, the bottle will be laid down with the wine in contact with the inner surface of the closure to promote aging of the wine. The use of a cork is considered by many connoisseurs to be necessary for this purpose. Although aging is a very complex chemical process, one contributing mechanism is a very slow reaction in the wine over time, often years, as a result of permeation of a minuscule amount of oxygen through the cork material. Therefore, it is important that a bottle closure for wine bottles does not impede this process.
There are asymmetrically configured closures, such as for champagne and fortified wines, that require additional equipment on the bottling line. When such bottle closures are provided by their manufacturer to a winery, the winery must add collating or detecting equipment in the wine line for detecting their orientations prior to insertion in the bottles.
Recently, plastic materials have been developed that simulate natural cork and are being used for less expensive wine. For these simulated cork closures, objective (a) and (b) as described above are still active and this modification can be applied to them with the same benefits as described for natural cork.
Traditionally, the neck and mouth of the bottle are enclosed with a capsule that protects the outer face of the closure against contamination, but does not obstruct permeation of air. While this tradition is still in use, in recent years the capsule has been eliminated by some wineries in favor of a compressible plastic or wax plug placed and retained in the neck of the bottle covering the outer face of the closure. Because this plug not only protects the face of the closure, but also seals it against permeation, it is considered to be appropriate only for common wines that will not significantly benefit from extensive aging.
For the foregoing reasons, there is a need for a bottle closure that is able to guide the entering position and the advancing direction of the corkscrew in an extraction operation; there is a need for making a bottle closure that will not impede the permeation of air; and there is also a need that the bottle closure contains guiding mechanisms in both ends of the closure for the convenience of production.